Color reversal process and developer

ABSTRACT

Rapid access positive color development of a silver halide photographic element is achieved by developing the element in a monobath which includes a photographic color developing agent, a black and white photographic developer, and a dye-formation inhibitor, to develop a black and white image. The element is thereafter treated to reduce the inhibiting action of the dyeformation inhibitor to permit formation of a colored, positive image.

United States Patent 11% Molenda May 13, 1975 [5 COLOR REVERSAL PROCESS AND 3.295.975 [H967 DEVELOPER 3,300,305 1/1967 3.331004 3/1967 [75] inventor: Robert P. Molenda, St. Paul, Minn. 3, 15 509 o/w'il [73] Assignee: Minnesota Mining and Manufacturing Company, St. Paul.

Primary E.tamim'rMary F Kelley [22] Filed: Aug. I4, 1972 Almrmy, Agent, or FirmAlexunder. Sell, Steldt & 211 Appl. No.: 280,263 Delahum Related [15. Application Data 57 ABSTRACT {63] Continuation-impart of Ser, No. 188.616. Oct. 12, Rapid access positive Color development of a Silver 197] halide photographic element is achieved by developing the element in a monobuth which includes a pho- [52] 96/59 zlgg ii tographic color developing agent, a black and white photographic developer, and u dye-formation inhibig gi SZ gQ ZZ Zg tor, to develop a black and white image. The element 1 0 is thereafter treated to reduce the inhibiting action of the dye-formation inhibitor to permit formation of a [56] UNITE SZ; K$S :Z?TENTS colored, positive image, 3,165,407 1/!965 McCarthy 96/22 32 Drawmgs COLOR REVERSAL PROCESS AND DEVELOPER This application is a continuation-in-part of US. application Ser. No. 188,616, filed Oct. I2, I971.

The present invention relates to photographic coior development technology, and more particularly relates to a color reversal monobath and a process for its use, and to photographic kits adapted to prepare such monobaths.

A widely used process for reversal color development of silver halide photographic films employs a succession of baths through which exposed photographic films must be passed. For example, a first bath may include a black and white developing agent which reduces silver halide in latent image areas of a film to silver, forming negative silver image therein. Thereafter the film may be uniformly exposed to light to form fog centers in undeveloped areas of the film, and then treated with a color developer solution in which a color developing agent reduces silver halide in the fogged areas to silver, and is itself oxidized. The oxidation product of the developer reacts with one or more color couplers which may be distributed throughout various layers of the film to form dyes therein. The silver images may then be bleached from the film, and unreacted silver halide may be removed therefrom by fix ing to thus provide positive, colored images. To avoid cross-contamination of the various processing baths, a number of intermediate wash baths are commonly employed. Further, a stop" bath is ordinarily utilized to halt black and white development immediately after treatment of the film in the black and white developer bath.

As will be evident from the above description, the process described employs many steps and utilizes many different processing baths. In addition, the shelflife of these prepared solutions are poor. Further, the above procedure must be very carefully regulated in order to provide satisfactory photographic color reproductions. Moreover, the time which is required to fully process an exposed roll of color film (a major cost factor) is inordinately long. A faster, more efficient, lessdetailed positive color development process is hence much to be desired.

It is an object of the present invention to provide a color developer monobath for rapid, positive color processing of a photographic element.

It is another object of the invention to provide a color reversal development process by which color photographic elements may be rapidly developed.

It is yet another object of the invention to provide a photographic color development kit from which the monobaths of the invention may be prepared.

Briefly, the present invention in one embodiment relates to a photographic color reversal development process which comprises:

A. treating a photographic element having a hydrophilic colloid (e.g., gelatin) silver halide layer hearing a latent image with an aqueous monobath which includes l. at least one photographic color developing agent, capable, upon oxidation thereof, of reacting with a photographic color coupler to form a dye;

2. at least one black and white developing agent having a polarographic half-wave potential at pH l0.0 of from about -lO millivolts to about l 87 millivolts, and

3. a water-soluble dye-formation inhibitor which is capable of preventing said color developing agent from coupling with a color coupler, thereby to imbibe the silver halide layer with the monobath and to develop solely a negative black and white silver image therein;

B. thereafter fogging the silver halide layer so as to render the layer developable in non-imaged areas;

C. without intermediate removal of the imbibed monobath, treating the layer to reduce the inhibiting effect of said dye-formation inhibitor, and

D. allowing development of a positive color image therein in the presence of a color coupler.

The practice of this invention includes the use of either photographic elements which contain couplers originally distributed in at least one emulsion layer or elements which contain spectrally sensitized silver halide and require the subsequent addition of color couplers as by a later bath solution.

Black and white and subsequent color development in the process of the present invention is believed to occur as follows:

Upon treatment of a silver halide photographic element bearing a latent image with the aqueous monobath described above, silver halide in latent image areas is reduced by the black and white developer to form a silver image. Because of the presence of the water-soluble dye-formation inhibitor. substantially no dye formation occurs at this time. Any of the color de veloper which has reduced silver halide (and which in turn has been oxidized) reacts with the dye-formation inhibitor (e.g., sulfite) to form a stable reaction product (e.g., a monosulfonate derivative). Dye formation during black and white development of the latent image is thus prevented. After black and white development ofthe latent image has been completed (so that substantially no reducible silver halide remains in latent image areas), the element is removed from the developer bath and is fogged," e.g., by exposure thereof to light, or by treatment thereof with known chemical foggants such as hydrazine, potassium borohydride, amine boranes, etc. At this point, the element still retains imbibed therein the monobath. Upon subsequent treatment of the element so as to reduce or eliminate the inhibiting effect of the dye-formation inhibitor in the imbibed monobath, color development of the element by the imbibed color developing agent may occur in those areas of the element which were fogged after black and white developing forming a positive colored image when color couplers are present.

The inhibiting effect of the dye-formation inhibitor may be reduced, for example, by treating the element with a composition which, for example, neutralizes or reduces the tendency of the inhibitor to form a reaction product with oxidized color developer. For example, when sulfite is employed as a dye formation inhibitor, the element may be treated with a solution of a sulfitereactive composition to neutralize sulfite in the imbibed monobath. The inhibiting effect of the dye formation inhibitor may be reduced, in a preferred embodiment. by decreasing the concentration of inhibitor in the imbibed layer, as by washing the imbibed layer with a solution which is capable of dissolving the inhibitor. Aqueous solutions of from about pH 7 to about pH 13 (most preferably above pH 10) are preferred for this procedure, particularly when sulfite is employed as the dyeformation inhibitor. Such solutions preferably include a basic ingredient such as sodium hydroxide, SO dium carbonate, trisodium phosphate dodecahydratc, etc, to render the solution alkaline, and may further include such photographic additives as sodium sulfite. fogging agents, surfactants, color couplers (particularly when a couplcnf'ree photographic element is to be developed to form a monochromatic image), etc. When sulfite is employed as the dyeformation inhibitor, then the washing solution is preferably chosen so as to be sulfitedissolving; i.e., it exhibits the capacity to remove sulfite from the imbibed monobath solution to thus per' ml! color development to occur. When the inhibiting effect is accomplished for example by forming an amine salt, the pH of the wash bath should be high enough to convert the salt to an amine. Although the solution preferably includes such additives arc exemplified above, satisfactory results have been obtained by simply washing the fogged element with water.

The dye-formation inhibitors of this invention may operate by selective reaction with oxidized color developer to prevent them from coupling to form a colored dye. The inhibitors may also act upon the developing agent to prevent its oxidation so that no colored dye is formed. For example, this latter inhibiting mechanism may be performed by blocking the amine group(s) on the color developing agents in the bath. The blocking may be accomplished, for example, by forming amine salts of the color developing agents (e.g., NHJCF, Nl-l CH hBri '*lNH(CHq)g Ol"l The particular conditions and parameters of the monobath solution depend to some degree upon the particular mechanism which is selected to inhibit the formation of dye by the coupling of developing agent and color coupler.

Where the dye formation inhibitor is selected so as to form with the oxidation product of the color developing agent a reaction product which is either colorless or removable, the following characteristics in the monobath are generally preferred:

A. The monobath should have a pH of about 8.5-14

(most preferably about pH 10.0-11.0);

B. The dye-formation inhibitor should be present in sufficient quantity so that substantially all dye formation in a silver halide photographic element is restrained in said monobath after exposure of said element therein to light.

Where the dye formation inhibitor acts by blocking the reactive amine group(s) of the color developing agent it may be desirable to have the pH of the bath below 8.5 and in many instances well below 7.0 (as low as 3.01.

With either mechanism, however, the developing agents must still possess half-wave potentials within the limits prescribed previously and hereinafter.

As used herein. photographic color developing agent refers to a compound capable of reducing silver halide to silver and in turn being oxidized, the oxidation product thereof being reactive with a photographic color coupler to form a dye. Photographic color developing agents of the p-phenylenediamine type (e.g., 2- methyl-4-lN-ethyl-N-(Banethylsulfonamidoethyl- )amino] aniline and 4-amino-N-ethyl-N-(B-hydroxyethyl)-ani1ine and their salts, are preferred. Such color developing agents are known to the art, and reference is made to Mees and James, Eds, The Theory ofrhe P|lltugraphlc Process, 3rd Ed, MacMill-an, New York,

1966, Chapter 17. Color developing agents having a polarographic half-wave potential at pH 1 1.0 of from about 159 millivolts to about 305 millivolts are par ticularly preferred.

By black and white photographic developer" employed herein, reference is made to one or more black and white developing agents which are capable of reducing silver halide to silver but which are incapable of reacting, in oxidized form, with a photographic color coupler to form a dye; this term includes mixtures of black and white developing agents, for examp1e,hydroquinone and 1-phenyl 3-pyrazolidin0ne. Such developing agents include those known to the art such as those ofthe hydroquinone series (e.g., hydroquinone, chlorohydroquinone, broniohydroquinone, methylhydroquinone, dichlorohydroquinone, omethoxyhydroquinone and catechol), those of the p-arninophenol series (e.g., N-methyl-p-aminophenol sulfate, p-hydroxyphenylgly cin and p-aminophenoll and those of the pyrazolidinonc series, particularly 3-pyrazolidinones such as 1phenyl-3-pyrazolidinonc. The black and white developing agents ofthe invention as defined above prcfera bly are further characterized by the formula wherein M is a cyclic organic nucleus (cg, benzene, pyrazolidinone) which includes no cyclic atoms other than carbon and nitrogen, Y is an OH group bonded to acyclic carbon atom of said nucleus, and X is a hydrogen atom or a hydroxyl, alkylamino, carboxyalkylamino, amino, alkyl or aryl group, X being bonded to acyclic atom of said nucleus. The black and White pho tographic developer of the invention includes at least one black and white developing agent having a polarographic half wave potential at pH 10.0 of from about -10 millivolts to about -l87 millivolts.

The use of half-wave potentials (E /z) for describing the useful developing agents, both color and black and white, is an efficient and meaningful way of characterizing the invention. Thermodynamically, the half-wave potential can be related to the reaction rate of the developing agents with silver halide. The greater the free energy of the reaction process, (here, the greater the tendency of the developing agent to release elections], the more positive is its oxidation halfwavc potential according to the Lewis and Randall Convention. Reference is made to Bent et a1,, Chemical Constitution, Elev trochemical, Photographic and Allergenic Properties of p-Amino-N-clialkylanilinci, J. Am. Chem. Soc., 73, 3 l00, 1951; Willis et al., The Relative Importance ofAdsorption and Electrode Potential in Determining the Rate of the Induction Process During Photographic Development. II. Hydmquinunes, Photographic Science and Engineering, Vol. 14, No. 2, pages 149-152 (1970); and Willis et al., The Relative Importance of Adsorption and Electrode Potential in Determining the Rate of the Induction Process During Photographic Development. I. The p-Aminuphennlx and p-Phenylenediamines, Photographic Science and Engineering, Vol. 14, No. 2, pages 1 4F148 (1970).

The Lewis and Randall Convention (G. N. Lewis and N. Randall, Therrriodynamlcs, McGraw Hill, New York, 1923, page 389) has been employed herein with respect to the values of polarographic half wave potential of black and white and color photographic developing agents. The polarographic half wave potentials referred to herein are oxidation potentials which may be experimentally determined by employing the method reported in Julian and Ruby. The Use ofStarionury Platinum Micmeltctrode in the Determination Qf Half Wave Potentials, J. Am. Chem. Soc. 72, 4719. 1950. the values being taken relative to the hydrogen electrode at pH 10.0 (black and white developing agents) or pH l L0 (color developing agents). The concentration of black and white developer in monobaths of the invention may be very low (eg. at least as low as 0.0045 moles/liter).

The particular controls used on a system depend, of course, upon the particular materials used. Since the basic desired mechanism of the process is to have the black and white developer favorably compete with the color developer for the image silver halide certain considerations must be given in the formulation of the monobath compositions. Where the black and white developer has a significantly higher half-wave potential than the color developer, there is already a strong tendency for the black and white developer to develop the image and a relatively weak color dye formation inhibitor (either by selection of material or low concentration) may be used. When there is not a substantial dif- TAHLE 0F SCME OXIDATION PULAHOGRAPHIC C OLOR DEVELOPERS pH of Measurement;

ference between the half-wave oxidation potentials of the two agents additional control must be effected over the monobath to insure the preferential development by the black and white agent. This may be done by increasing the strength of the dye-formation inhibitor (by selection of material or increasing the concentration of such) and/or increasing the tendency of the black and white agent to develop the image by increasing the concentration of that agent. ln general. however. the parameters of half-wave potentials used in describing the useful developing agents define the limits of useful materials for each category of developing agents. That means, for example. that a black and white developer with a half-wave potential at pH ll) of less than l87 millivolts will not produce satisfactory results in this process even by exercising the known controls over the reaction mechanisms. The process can be performed with substantially all developing agents selected from within the half-wave potential ranges for each of the agents. The half-wave potential therefore satisfactorily generically describes the materials which can be used in this process.

A listing of some known developing agents and their half-wave potentials follows:

HAM -l-JAVE POTENTIALS Compound CH CH it:t+-N 279) 266.0 -222.0 N,N-dietityl-p-phenylenediamine CH UH CH3 H N-tl(ethy1) -321.5 -229.0 490.0 E-amino-S-d1ethylaminotoluene (co-2) ,Etl'tjl H N lk 4269.5 -2 '.O 490.0 4-a.m.ino-ll-etth,yl-N-( methane-sulfonamidoethyl] CH CH S0 CH mtoluidine (cu-3) 3 ,am l H N-G- N -188 .0 t-anino-E-methyl-N-ethyl-M'p Judt'oityethyl) CH CH OH aniline (ent) TABLE OF SQIB OXIDATIW POLARWRAPHIC HALF-HAVE POTENTIAIS (CONTINUED) BLACK &. WHITE pH of Measurement DEVEOERS Compound Cl H0608 -256.0 -l8l.O 4.52.0 chlorohydroquinone s H0-OH 481.0 4.26.0 -29.0 nethyltwdroquinone PIG-@011 -2o6.o -166.0 429.0 hydroquiuone -215 .0 -l +l .0 phenidoae SO3H H0 0H 4%.!) -l88-0 (borderline utility] rwdroquinone monoaulfonate H O C NHNH (outside useful range) 491-5 -l5l.5 hydroquinone mouocarboxyllc acid hydrazide This table simply illustrates that these black and white developers are more reactive than these color developers, using the oxidation half-wave potentials as an index of their reactivity. The more positive the number. the more reactive is the particular developer, at any given pH. The change in half-wave potential with pH is expected. and indicates that the developers (any devel operl become more reactive as the pH is increased. The lesser reactive black and white developers, phenidone and hydroquinone monosulfonate are noteworthy because these developers are not reactive enough to scavenge silver halide before the color developer pres ent can react to form a dye image. Developers (black and white developers} which are more reactive than these representative developers (that is more reactive than phenidone and hydroquinone monosulfonatel are found to give excellent positive images when used in the manner described in our invention.

Good results are obtained when the color developing agent contributes at least 40 percent up to about 95 mole percent of the total moles of developer (black and white plus color developing agents).

It is further desired that the monobaths of the invention include at least 0.02 moles/liter up to the solubility limit of color developing agent in the monobaths. Preferably, from about 0.06 to 0.10 moles of color developing agent per liter is employed.

The water-soluble, dye-formation inhibitor which is preferably employed in the present invention is a com position, such as sulfite, which is capable of reacting with oxidized color developer which may be formed during the black and white development step to form therewith a stable reaction product. Sulfite is preferred. By sulfite" as used herein, reference is made to sulfite and bisulfite compounds which, when dissolved in wa ter, liberate sulfite ion. Preferred sources of sulifte ion include ammonium sulfite and the alkali metal sulfites such as sodium sulfite, potassium sulfite, etc, particularly sodium sulfite. The monobath of the invention must contain sufficient dye-formation inhibitor to re strain substantially all dye formation in the silver halide photographic element in the monobath after exposure of the element in the monobath to light. In its preferred embodiment, the monobath of the invention employs inhibitor (e.g., sulfite) in a concentration of 0.10 moles/liter and more preferably from about 0.15 to about 0.48 moles/liter. For purposes of permitting rapid color development to occur, it is preferred that the mole ratio of sulfite/color developer be at least 0.97 and more preferably L46 to 7.8. Other suitable dyeformation inhibitors which form reactive products with oxidized color developing agents include ascorbic acid, citrazinic acid, 4-hydroxy3-butanone, etc.

Other such dye-formation inhibitors include hydroquinone monocarboxylic acid hydrazine. Dyeformation inhibitors of this type which form reaction products with oxidized color developing agents and which are useful in the invention may be selected by reference to the following simple test:

To 50 milliliters of an aqueous test solution containing 0.3 grams of 2-methyL4-diethylamino aniline hydrochloride, 0.05 grams of l-hydroxy-N-[B-(Z- acetamidophenyl)-ethyl]-2-naphthamide and 2.0 grams of sodium carbonate are added 0006 moles of a candidate dye-formation inhibitor. To the resulting solution, after mixing, is added 2 drops of an aqueous solution containing, per liter, 75 grams of potassium ferricyanidc. Absence of the development of color in the solution upon addition of the ferricyanide solution indicates that the candidate compound is a dyeformation inhibitor of the invention.

Those materials known in the photographic industry as competing couplers or colorless couplers suitably act as dyeformation inhibitors in the practice ofthis invention. For example, US, Pat. No. 2,742,833 lists a num ber of competing couplers which would be suitable as inhibitors which form reaction products with oxidized color developing agents in this invention.

Dye'ft'irmation inhibitors which act to prevent oxidation ofthe color developer may be chosen according to the following test:

Any compound which when added to the monobath system reversibly reduces the oxidation potential of the color developer below that of silver is effective as an inhibitor which prevents oxidation of the color developing agent. This may readily be measured by known electrolytic cell techniques. By reversible it is meant that some alteration of condition in the bath or subsequently added material can regenerate the color developing agent from the blocked color developing agent.

it is within the scope of this invention to block the color developing agent prior to its addition to the black and white developer. That is, it is within the scope of the invention to add the color developing agent and dyc-formation inhibitor as one compound, for example. by adding the color developing agent in its already in hibited form. This form may be for example a blocked amine salt or a complex of the color developing agent.

The monobaths of the invention may, of course, in clude various other photographic adjuvants such as bromide ion. surfactants, color couplers, benzyl alcohol, ethylene gylc-ol, thiocyanates and the like.

After development of the colored, positive image, the ordinary process steps normally used in finishing the picture should be used here. That after the bath to remove the inhibiting effect. there should be an acid stop bath, then bleach bath, fix bath (or bleach/fix bath}, wash, and stabilizing bath. Hardeners may be added to any or all of the stop, bleach, fix or bleach/fix baths, or a prehardening bath may be used prior to development in the monobath. The compositions of such baths are well known in the art and need not be discussed here.

Between the development bath and the bath to remove the inhibitor a quick wash step has been found desirable to remove the solution retained on the surface of the photographic element so as to prevent contamination of the latter bath. This wash is not of sufficient length of intensity as to reduce the inhibiting effeet, but is only used to remove the solution held by surface tension on the photographic clement. Of course if one is using water as the inhibitor removing second bath such a quick wash would be unnecessary.

Although the photographic color developer monobaths of the invention are surprisingly stable over extended time periods in solution form, it may be desirable from a commercial standpoint to provide color developer kits from which the monobaths of the invention maybe prepared. Accordingly, in another embodiment the present invention relates to a color developer kit from which can be prepared positive-acting color devclopment monobaths for color development of silver halide photographic elements. The kit comprises a plurality of packages containing predetermined quantities of developer monobath ingredients, the kit including A. at least one photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic color coupler to form a dye. B. at least one black and white developing agent haw ing a polarographic half-wave potential at pH I of from about millivolts and about l87 millivolts; and

C. sulfitc in sufficient quantity to provide a sulfite/'- color developer mole ratio of at least 0.97 (and preferably 1.46 to about 7.8).

In a two-package kit. for example, one package may contain an acidic solid or aqueous liquid which includes sulfite, color developing agent and black and white developer, and the second package may contain an alkaline concentrated liquid or solid which includes an alkaline substance such as sodium hydroxide, a source of bromide ion and sulfite. A three-package kit may have a first package which includes a concentrated, acidic solid or aqueous liquid containing a color developing agent plus sulfite, a second package which includes a concentrated acidic solid or aqueous liquid which contains the black and white photographic developer plus sulfite. and a third package containing a concentrated alkaline solid or aqueous liquid which includes a base such as sodium hydroxide, a source of bromide ion, and sulfite. For reasons of economy, it is desired that each package be made as concentrated practicable. Although it is desired that the contents of each package be in solution form, it may be desirable in some instances to provide certain of the package contents in the form of aqueous dispersions, thereby enabling high concentrations of ingredients to be achieved and further promoting easy dissolution of the dispersed ingredients when the working monobath is prepared. It may be desirable to some instances to provide the monobath ingredients in solid, preferably powdered form. The contents of each package of the kits of the present invention are carefully premeasured so that the monobaths of the invention may be prepared by adding the entire contents of each package sequentially to water, and diluting to a predetermined volumev Thus, sufficient basic material (e.g., sodium hydroxide) must be included within the kit to provide the resulting monobath with a pH of from 8.5-)4, sufficient dye formation-inhibitor must be provided so that the resulting monobath does not permit dye formation to occur during black and white development therein of a photographic element. etc. In preparing monobaths of the invention, tag, from developer kits, color developing agent solubility problems are largely avoided by first forming an aqueous solution of color developing agent, and thereafter adding the alkaline ingredients thereto.

in the practice of this invention, when it is stated that there is substantially no dye formation, it is meant that no colored form of a dye which cannot be removed from the photographic element is formed. The formation of colorless dyes or intermediates or readily removable (e.g., water soluble) dyes is not the type of dye formation which must be restrained in the practice of this invention.

The invention may be more readily understood by reference to the following illustrative, non-limiting examples:

EXAMPLE 1 A gelatino silver halide photographic film containing red, green, and blue-sensitive layers (the layers containing appropriate color couplers dispersed therein by a solvent dispersion technique) was exposed through a grey wedge (continuous, logarithmic density wedge) in S a scnsitometer and was developed for 3 minutes at 70F. in total darkness in a monobath of the following composition:

l0 Water 800 ml.

Sodium hexametaphosphate g. Z-methyl 4-tlietbylamino aniline (color developer) I20 g. Sodium sullite 50 g Hydroquinonc h g.

Sodium carbonate (anhydrous) 40 g.

l5 Potassium bromide 2.0 g.

Water to I000 ml.

Thereafter, the film carrying imbibed monobath was 20 placed in an aqueous solution containing 40 g. per liter of sodium carbonate. and was exposed therein to light for 3 minutes. The film was then washed with water, bleached for 2 minutes in a bleaching bath consisting of Water 900 ml. Potassium ferrieyanide 75 g. Potassium bromide l5 g.

Glacial acetic acid l0.0 mi. 1 Sodium acetate 50 g. Potassium aluminum sulfate l5.0 g.

Water to I000 ml.

was washed again, and then treated for 2 minutes with a conventional fixing solution of the following composition:

Water 500 ml. Sodium thiosulfate 240 g. Sodium sulfite l5.0 g.

Glacial acetic acid 480 ml.

Boric acid 75.0 g. Potassium aluminum sulfate 15.0 g. Water to [000 ml.

After washing and drying, the film bearing a positive color image exhibited the following densitometric properties:

Dmin Dmax to Blue light (yellow density) 0.58 2.93 to Green light (magenta density) L62 3. l6 to Red light (cyan density) 0.92 3.42

EXAMPLE 2 Example I was repeated exactly except that the aqueous sodium carbonate solution was replaced with distilled water. Similar results were obtained.

EXAMPLE 3 A silver halide photographic element similar to that employed in Example was exposed through a grey wedge to light and then developed for 5 minutes at F in total darkness in a developer monobath of the following composition:

Water 800 ml. Sodium l'lfi hinlclllpl'ltlSphlllt 2.0 g. lmcth Ltdiethylamino aniline 12.0 g. Sodium sulfitc 50.0 g. Chloroh)droquinone 6.0 g. Sodium carbonate (anhydrous) 40.0 g. Potassium bromide 2.0 g. Water to lll ml.

The film was then treated according to the procedure of Example 1. The following densitometric results were obtained:

Dmin Dmax to Blue light 0.30 3.30

to Green light 052 3.10

to Red light 0.60 3.76

EXAMPLE 4 A silver halide photographic element similar to that employed in Example 1 was exposed to light through a grey wedge and then developed for 5 minutes at 70F. in total darkness in a developer monobath of the following composition:

Water 800 ml. Sodium hexametuphosphate g. Z-meth l-J-diethylamino aniline l2.0 g. Sodium sulfite 50.0 g. Methyl-pam-ummophenol sulfate 60 g. Sodium carbonate lanhydrousl 40.0 g. Potassium bromide 2.0 g. Water to I000 ml.

The film was then processed in accordance with Example l. The following densitometric properties were obtained:

Dmin Dmax to Blue light 0.50 3.42

to Green light [.20 2.92

to Red light 0.80 3.70

EXAMPLE 5 Example 1 was duplicated exactly with similar photographic material except that, in the monobath. 9.0 g. of p-hydroxyphenylgylcin was substituted for hydroquinone. The following densitometric properties were obtained:

Dmin Dmax to Blue light 0.30 2.88

to Green light 086 3.72

to Red light 070 3.52

EXAMPLE 6 A photographic silver halide color reversal film similar to that employed in Example 1 was exposed through a grey wedge in a sensitometer and was then developed for 3 minutes at 70F. in total darkness with agitation in a developer monobath of the following composition:

Water ml. Sodium hexametaphosphtite p-lN-ethyl-N[i-hydroxyeth)lluminoaniline (color developer] Potassium sulfite Hydroquinone l phen}l-3--pyruzolidinone Potassium hromide -1) Sodium carbonate (anhydrousl Sodium hydroxide \Nater to The film was thereafter placed in a second bath of:

Water 300 ml. Na PO lZ H 0 40 g. Sodium hydroxide 40 g. Water to I000 ml.

and was reexposed to room light illumination therein for 3 minutes. The film was then washed, bleached, fixed. washed and dried according to the procedure of Example I. The following densitomctric properties were obtained:

Dmin Dmax to Blue light 0.35 4.80

to Green light 0.l6 2.24

to Red light 0.l2 3.50

EXAMPLE 7 A color reversal silver halide photographic film similar to that of Example 6 was exposed to a light image and then developed for 4 minutes at F. in total darkness in a developer monobath of the following composition:

Water 800 ml. Sodium hexametaphosphate 2.0 g. Potassium sulfite 48.0 g. Benzyl alcohol 3.5 g. Ethylene glycol 4.5 g. p-( N-ethyl-N-B-hydroxyethyll aminoaniline, sulfate salt 18.0 g. Hydroquinone 7.5 g. l-phenyl-3pyrazolidinone 0.30 g. Sodium thiocyanate 0.5 g. Potassium bromide 2.0 g. Potassium iodide 0.0l g. Sodium carbonate (anhydrous! 30.0 g. Sodium hydroxide 4.0 g. Water to I000 ml.

Short Stop Solution Glacial acetic acid l2.0 ml. Sodium acetate 6.3 Water to I000 ml.

Bleach Bath Dmin Dmax Water 800 ml. Potassium lerricyanide l ill) g. to Red light 0458 07] Potassium bromide 24.0 gv Disodium hydrogen phosphate 12.0 g. Sodium thioc \anate llfi g. Q Sodium dihydrogen phosphate I15 3. Water to woo ml. EXAMPLE Fixing Bath A silver halide color photographic clement of the w my; type described in Example l was exposed to light mlf lhitlfiulllfllc no 0 through a grey wedge and then developed for 3 minutes Ll UK? SO UllOnl g gflghisume 2m) m at 70F. in total darkness in the developing solution Water to 1000 ml monobath of Example 1. The film was then immersed for 3 minutes in a second bath, maintaining total dark- The following densitometric properties were obtained: ness conditions. The second bath consisted of:

Water 1000 ml, (total) D Sodium carbonate ianhydrous) 40 g. Dmm m Potassium horohydride 0.05 g.

to Blue light 0.1) 5.20 The film thereafter was fixed in the fixing solution of to Red light 0.08 3.58

Example 1 for 2 minutes, also in total darkness. and was then further washed. bleached. fixed, washed and dried in accordance with Example I. The film. now EXAMPLE 8 bearing a positive color image, exhibited the following Example I was duplicated exactly except that the densllomfitrlc characteristics: amount of hydroquinone was reduced from 6 grams to 2 grams in the monobath solution. The following densi- Dmin Dmax tometric properties were obtained:

to Blue light 0.2] 2.27 to Green light 042 3.10 Dmin Dmux in Red llght 0.78 t 38 to Blue light 096 4.70 to Green light 0.86 3.36 to Red light 062 2.22 EXAMPLE 1 A color reversal silver halide photographic material similar to that of Example 6 was exposed to light EXAMPLE 9 through a grey wedge and then developed for 4 minutes A photographic sflver halide black and white man? at 70F. in total darkness m a developer solution of the rial (coupler-free) was exposed through a grey wedge following composition:

in a sensitometer and was then developed for 2 minutes at 70F. in total darkness in a developer monobath re- Water 800 ml. sulting from combining 300 ml, of the following solu- Sodium hexametaphosphate 21) tion A with the following solution B: P- -s y N-fiy y y J- aminoanilme. sulfate salt 180 g. 4 Potassium sulfite 20.0 g. Solution A HydroquironedMonocarhoxylic l 5 Water 800 acid y razi e g Potassium bromide 2.0 g. 0dlum hexdmelaphisphale Sodium carbonate (anhydrous) 30.0 g. :g: g Sodium hydroxide 4.0 g. Sodium sun-"e 6 g: Water to I000 ml. Hydroquinone 6.0 g. I 1 g ii (anhydrous) 3-8 2- The film was thereafter treated in accordance with Exfi l? e 1000' f ample 6. The following densitometric properties were obtained:

Solution B 5 Water 50 ml. Dmin Dmax Sodium carbonate 2.0 g. N-(i-hydroxy-Z-naphthoyli- 3 1' in ()70 2."0 l'F I: Gr ezn light 0:44 4.iu aniline (cyan coupler) 3.0 g. to Red light (L 41" The film was then laced in an a ueous solution conp q EXAMPLE 12 taming 40 g. per liter of sodium carbonate, and exposed to room light illumination therein for 3 minutes. The A color reversal silver halide photographic element film was then washed, bleached, fixed, washed and similar to that of Example 6 was exposed to light dried in accordance with Example 1. A positive color through a grey wedge and then developed for 3 minutes monochrome image having the following densitometric at F. in total darkness in a developer monobath of properties was obtained: the following composition:

The film was thereafter immersed in a second bath of the following composition and re-exposed therein to room light illumination for 3 minutes:

Water Sodium phosphate dodecahydrate 4.0 g. Sodium hydroxide 4.0 g. Water to 1000 ml.

The fiom was thereafter washed, bleached, fixed, washed and dried according to Example l. The following densitometric properties were obtained:

Dmin Dmax to Blue light 055 2.30

to Green light 042 1.46

to Red light 052 2.60

EXAMPLE 13 A kit for preparing a monobath of the invention was formulated as follows into two packages:

Package A Sodium hexametaphosphate 2.0 g. p-( N-ethyl-I'd-Bhydroxyethyl laminoaniline 18.0 g. Potassium sulfite 48.0 g. Hydroquinone 7.5 g. 1-pheny1-3-pyrazolidinone 0.30 g.

m2- Sodium carbonate 30.0 g. Sodium hydroxide 4.0 g. Potassium bromide 2.0 g.

in use, the contents of package A are dissolved in 700 ml. of water, and the contents of package B are dissolved in 200 ml. of water. The resulting solutions are then combined and diluted to 1000 ml. to provide a working monobath solution of the invention.

EXAMPLE 14 This example illustrates the inhibiting mechanism whereby oxidation of the color developer is prevented by blocking the developer.

Developer Composition Calgon" 2.0 g CD2" 12.0 g Sodium Sulfite 50.0 g Amidol 10.0 g Potassium Bromide 2.0 g Water dilute to 1000 ml Na hcxametaphosphatc 2 -aminodicthyla|minotulucnc monoh ydrochluride Ferrania Mark III cine positive release film was used to reduce this invention to practice. This material can be processed reversally to yield color positive transparencies of good quality and may be considered representative of any commercially available negative acting color silver halide material or any color silver halide material designed for conventional reversal processing. The color couplers in the material are resin dispersed, although the invention is not limited to such a particular composition. The construction of the trip-ack is adequately described in the prior art.

A test strip of this material was exposed on an EK l 01 sensitometer for 2 seconds before a logarithmic step wedge. This strip was processed in the development formulation described in this example for 4 minutes at F in total darkness. After this development period, the test strip was removed from the development bath and placed in a bath containing 40.0 g/l of Na CO for 3 minutes while being exposed to room light illumination. During this time, dye formation was noted to take place. After this period, the test strip was subjected to conventional ferricyanide bleach, wash, stop-fix, wash and stabilization steps; any step of which does not impose any limitations on this invention. This treatment resulted in the production of a color positive image of the following densitometric characteristics:

lfa water wash bath is used for the re-exposure step, no dye density is produced in the test strip, indicating that the pH rise of this example is necessary to activate the color developer.

Although the sulfite concentration in this example is such as could be sufficient to act as an inhibitor by forming a reaction product with oxidized color developing agent, the pH of this bath is such that there can be no oxidation of the color developer. The sulfite is present only as a stabilizer and does not here inhibit coupling of oxidized color developer, as there is none until the pH is raised.

What is claimed is:

1. A bath for photographic positive color development of silver halide photographic elements, said bath comprising, in aqueous solution at a pH of from 8.5 to 14:

A. at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye; said color developing agent having a polarographic half-wave potential at pH 1 1.0 from about l59 to about 305 millivolts;

B. at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about -10 millivolts to about -l87 millivolts; and

C. water-soluble, dye-formation inhibitor in a concentration of at least about 0.10 moles/liter which is present in sufficient quantity so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97.

2. The bath according to claim 1 wherein said dyeformation inhibitor is sulfite.

3. The bath according to claim 1 wherein the pH thereof is from about l to about I l.

4. The bath according to claim 1 wherein the dyeformation inhibitor is capable of forming a reaction product with the oxidation product of said color devel oping agent.

5. The bath according to claim 1 wherein the dyeformation inhibitor is capable of preventing the coior developing agent from being oxidized.

6. The developer bath according to claim 1 wherein said color developing agent represents from about 40 to about 95 mole percent of the total developer content of said bath.

7. The developer bath of claim 1 wherein said at least one black and white photographic developing agent is hydroquinone.

8. The developer bath according to claim 1 which ad ditionally includes a color coupler compound,

9. The developer bath according to claim 1 wherein said at least one color developing agent has a polaro graphic half-wave potential at pH l l.0 of from about -l59 millivolts to about 305 millivolts.

10. The bath of claim 1 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid, 4-hydroxy-3-butanone and hydroquinone monocarboxylic acid hydrazides.

11. The bath of claim 1 wherein the pH is at least 10.0.

12. A color developer bath for positive color development of silver halide photographic elements, said bath comprising, in aqueous solution of pH 85-14,

A. at least 0.02 moles/liter of primary aromatic amine photographic color developing agent capable, upon oxidation thereof, of reacting with a photographie color coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH l 1.0 of from about -l59 to about 305 millivolts;

B. at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about l0 millivolts to about l87 millivolts; and

C. from about 0, l0 to about 0.48 moles/liter of inhibitor which is present in sufficient quantity so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, and which forms a reaction product with oxidized said color developing agent, the mole ratio of inhibitor to color developer being at least about 0.97.

13. The developer bath according to claim 12 wherein said inhibitor is sulfite.

14. The developer according to claim 12 wherein said black and white photographic developer includes hydroquinone and l-phenyl-3-pyrazolidinone.

15. A photographic color reversal development pro cess which comprises A. treating a color photographic element having a hydrophilic colloid silver halide layer bearing a latent image with an aqueous bath solution which in cludes at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation, of reacting with a photographic Color coupler to form a dye, black and white photographic developer including at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about l0 millivolts to about l87 millivolts, and water-soluble dye-formation inhibitor in a concentration ofat least 0.10 moles/- liter, said concentration being sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to the light. the mole ratio ofinhibitor to color developer being at least about 0.97. thereby to imbibe said silver halide layer with said bath solution and to develop solely a negative black and white image therein;

B. thereafter fogging said silver halide layer so as to render said layer dcvelopable in non-imaged areas:

C. without intermediate removal of said imbibed bath solution, treating said layer to reduce the inhibiting effect of said dye formation inhibitor; and

D. allowing development therein of a positive color image in the presence of a color coupler.

16. The process according to claim 15 wherein said color coupler is originally in the photographic element,

17. The process according to claim 15 wherein at least some of the presence of color coupler is supplied by a bath.

[8. The process according to claim 15 wherein the fogging and reduction of inhibiting effect is performed in the same bath.

19. The process according to claim 15 wherein said element is washed with an inhibitordissolving aqueous solution after said fogging step.

20. The process according to claim 15 wherein said fogging step comprises exposing said film bearing said black and white silver image to light.

21. The process according to claim 15 wherein said fogging step comprises treating said film bearing said black and white silver image with a fogging agent.

22. The process according to claim 15 wherein the pH of the bath is about 8.5-l4.

23. The process according to claim 15 wherein any baths of the group selected from stop baths, bleach baths, fix baths, bleach/fix baths, wash baths, stabilizing baths, or hardening baths are also used.

24. A photographic color reversal development process which comprises A. treating a photographic element having a hydrophilic colloid silver halide layer bearing a latent image with an aqueous alkaline bath which includes at least 0.02 moles/liter of primary aromatic amine color developing agent capable, upon oxida tion thereof, of reacting with a photographic coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 1 1.0 of from about l 59 to about 305 millivolts, black and white photographic developer which includes hydroquinone, and from 0.10 to 0.48 moles/liter of inhibitor in a concentration sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97, thereby to imbibe said bath into said silver halide layer and to develop solely a negative black and white silver image therein;

B. thereafter fogging said silver halide layer by exposure thereof to light; and

C. without intermediate removal of imbibed bath,

washing said layer with an inhibitor-dissolving aqueous alkaline solution until a positive color image has been developed therein.

25. The process according to claim 24 wherein said inhibitor is sulfite.

26. A color developer bath for photographic positive color development of silver halide photographic elements, said bath comprising, in aqueous solution of pH 85-14.

A. at least 0.02 moles/liter of a photographic color developing agent capable of reacting with a photographic color coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH l 1.0 of from about l59 to about 305 millivolts;

B. a black and white photographic developer including at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about l millivolts to about l87 millivolts; and

C. a water-soluble, dye-formation inhibitor in a concentration of at least about 0.10 moles/liter which is capable of reacting with the oxidation product of said color developing agent to form a stable, soluble complex and which is present in sufficient quantity so that substantially all dye formation of a silver halide photographic element is restrained in said bath after exposure of said element to light, the mole ratio ofinhibitor to color developer being at least about 0.97.

27. A photographic color reversal development process which comprises A. treating a photographic element having a hydrophilic colloid silver halide layer bearing a latent image with an aqueous alkaline bath which includes at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation of reacting with a photographic color coupler to form a dye, black and white photographic developer including at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about l0 millivolts to about l87 millivolts, and water-soluble dye-formation inhibitor in a concentration sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, and of at least about 0.10 moles/liter, the mole ratio of inhibitor to color developer being at least about 0.97, thereby to imbibe said silver halide layer with said bath and to develop solely a negative black and white silver image therein;

B. thereafter fogging said silver halide layer so as to render said layer developable in non-imaged areas; and

C. without intermediate removal of said imbibed bath, treating said layer to reduce the inhibiting effect of said dye formation inhibitor, thereby to cause development therein of a positive color image.

28. A bath for photographic positive color development of silver halide photographic elements said bath comprising in aqueous solution at a pH of from 8.51 4;

A. at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye. said color developing agent having a polarographic half-wave potential at pH 1 1.0 of from about l 59 to about 305 millivolts,

B. at least one black-and-white developing agent having a polarographic half-wave potential at pH 10.0 of from about l0 millivolts to about l87 millivolts, and

C. water-soluble, dye-formation inhibitor in a concentration which is sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97.

29. The bath of claim 28 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid, 4-hydroxy-3-butanone and hydroquinone monocarboxylic acid hydrazides.

30. A bath for photographic positive color development of silver halide photographic elements, said bath comprising in aqueous solution at a pH of from 8.5l41

A. at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 1 1.0 of from about 159 to about 305 millivolts,

B. at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 greater than that of phenidone to 10 millivolts, and i C. water-soluble, dye-formation inhibitor in a sufficient concentration so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97.

31. The photographic developer bath of claim 30 in which dye formation inhibitor is present in a concentration of at least about 0. l0 moles/liter.

32. The bath of claim 30 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid 4-hydroxy-3-butanone, and monocarboxylic acid hydrazides. 

1. A BATH FOR PHOTOGRAPHIC POSITIVE COLOR DEVELOPMENT OF SILVER HALIDE PHOTOGRAPHIC ELEMENTS, SAID BATH COMPRISING, IN AQUEOUS SOLUTION AT A PH OF FROM 8.5 TO 14: A. AT LEAST 0.02 MOLES/LITER OF PHOTOGRAPHIC COLOR DEVELOPING AGENT CAPABLE, UPON OXIDATION THEREO, OF REACTING WITH A PHOTOGRAPHIC COUPLER TO FORM A DYE; SAID COLOR DEVELOPING AGENT HAVING A POLAROGRAPHIC HALF-WAVE POTENTIAL AT PH 11.0 FROM ABOUT -159 TO ABOUT -305 MILLIVOLTS; B. AY LEAST ONE BLACK AND WHITE DEVELOPING AGENT HAVING A POLAROGRAPHIC HALF-WAVE POTENTIAL AT PH 10.0 OF FROM ABOUT -10 MILLIVOLTS TO ABOUT -187 MILLIVOLTS; AND C. WATER-SOLUBLE, DYE-FORMATION INHIBITOR IN A CONCENTRATION OF AT LEAST ABOUT 0.10 MOLES/LITER WHICH IS PRESENT IN SUFFICIENT QUANTITY SO THAT SUBSTANTIALLY ALL DYE FORMATION OF A SILVER HALIDE PHOTOGRAPHIC ELEMENT IS RESTRAINED IN SAID BATH AFTER SAID ELEMENT HAS BEEN EXPOSED TO LIGHT, THE MOLE RATIO OF INHIBITOR TO COLOR DEVELOPER BEING AT LEAST ABOUT 0.97.
 2. The bath according to claim 1 wherein said dye-formation inhibitor is sulfite.
 3. The bath according to claim 1 wherein the pH thereof is from about 10 to about
 11. 4. The bath according to claim 1 wherein the dye-formation inhibitor is capable of forming a reaction product with the oxidation product of said color developing agent.
 5. The bath according to claim 1 wherein the dye-formation inhibitor is capable of preventing the color developing agent from being oxidized.
 6. The developer bath according to claim 1 wherein said color developing agent represents from about 40 to about 95 mole percent of the total developer content of said bath.
 7. The developer bath of claim 1 wherein said at least one black and white photographic developing agent is hydroquinone.
 8. The developer bath according to claim 1 which additionally includes a color coupler compound.
 9. The developer bath according to claim 1 wherein said at least one color developing agent has a polarographic half-wave potential at pH 11.0 of from about -159 millivolts to about -305 millivolts.
 10. The bath of claim 1 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid, 4-hydroxy-3-butanone and hydroquinone monocarboxylic acid hydrazides.
 11. The bath of claim 1 wherein the pH is at least 10.0.
 12. A color developer bath for positive color development of silver halide photographic elements, said bath comprising, in aqueous solution of pH 8.5-14, A. at least 0.02 moles/liter of primary aromatic amine photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic color coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 11.0 of from about -159 to about -305 millivolts; B. at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about -10 millivolts to about -187 millivolts; and C. from about 0.10 to about 0.48 moles/liter of inhibitor which is present in sufficient quantity so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, and which forms a reaction product with oxidized said color developing agent, the mole ratio of inhibitor to color developer being at least about 0.97.
 13. The developer bath according to claim 12 wherein said inhibitor is sulfite.
 14. The developer according to claim 12 wherein said black and white photographic developer includes hydroquinone and 1-phenyl-3-pyrazolidinone.
 15. A PHOTOGRAPHIC COLOR REVERSAL DEVELOPMENT PROCESS WHICH COMPRISES A. TREATING A COLOR PHOTOGRPHIC ELEMENT HAVING A HYDROPHILIC COLLOID SILVER HALIDE LAYER BEARING A LATENT IMAGE WITH AN AQUEOUS BATH SOLUTION WHICH INCLUDES AT LEAST 0.02 MOLES/LITER OF PHOTOGRAPHIC COLOR DEVELOPING AGENT CAPABLE, UPON OXIDATION, OF REACTING WITH A PHOTOGRAPHIC COLOR COUPLER TO FORM A DYE, BLACK AND WHITE PHOTOGRAPHIC DEVELOPER INCLUDING AT LEAST ONE BLACK AND WHITE DEVELOPING AGENT HAVING A POLAROGRAPHIC HALF-WAVE POTENTIAL AT PH 10.0 OF FROM ABOUT -10 MILLIVOLTS TO ABOUT -187 MILLIVOLTS, AND WATER-SOLUBLE DYE-FORMATION INHIBITOR IN A CONCENTRATION OF AT LEAST 0.10 MOLES/LITER, SAID CONCENTRATION BEING SUFFICIENT SO THAT SUBSTANTIALLY ALL DYE FORMATION OF A SILVER HALIDE; PHOTOGRAPHIC ELEMENT IS RESTRAINED IN SAID BATH AFTER SAID ELEMENT HAS BEEN EXPOSED TO THE LIGHT 4THE MOLE RATIO OF INHIBITOR TO COLOR DEVELOPER BEING AT LEAST ABOUT 0.97, THEREBY TO IMBIDE SAID SILVER HALIDE LAYER WITH SAID BATH SOLUTION AND TO DEVELOP SOLELY A NEGATIVE BLACK AND WHITE IMAGE THEREIN; B. THEREAFTER FOGGING SAID SILVER HALIDE LAYER SO AS TO RENDER SAID LAYER DEVELOPABLE IN NON-IMAGED AREAS; C. WITHOUT INTERMEDIATE REMOVAL OF SAID IMBIDED BATH SOLUTION, TREATING SAID LAYER TO REDUCE THE INHIBITING EFFECT OF SAID DYE FORMATION INHIBITOR; AND D. ALLOWING DEVELOPMENT THEREIN OF A POSITIVE COLOR IMAGE IN THE PRESENCE OF A COLOR COUPLER.
 16. The process according to claim 15 wherein said color coupler is originally in the photographic element.
 17. The process according to claim 15 wherein at least some of the presence of color coupler is supplied by a bath.
 18. The process according to claim 15 wherein the fogging and reduction of inhibiting effect is performed in the same bath.
 19. The process according to claim 15 wherein said element is washed with an inhibitor-dissolving aqueous solution after said fogging step.
 20. The process according to claim 15 wherein said fogging step comprises exposing said film bearing said black and white silver image to light.
 21. The process according to claim 15 wherein said fogging step comprises treating said film bearing said black and white silver image with a fogging agent.
 22. The process according to claim 15 wherein the pH of the bath is about 8.5-14.
 23. The process according to claim 15 wherein any baths of the group selected from stop baths, bleach baths, fix baths, bleach/fix baths, wash baths, stabilizing baths, or hardening baths are also used.
 24. A photographic color reversal development process which comprises A. treating a photographic element having a hydrophilic colloid silver halide layer bearing a latent image with an aqueous alkaline bath which includes at least 0.02 moles/liter of primary aromatic amine color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 11.0 of from about -159 to about -305 millivolts, black and white photographic developer which includes hydroquinone, and from 0.10 to 0.48 moles/liter of inhibitor in a concentration sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97, thereby to imbibe said bath into said silver halide layer and to develop solely a negative black and white silver image therein; B. thereafter fogging said silver halide layer by exposure thereof to light; and C. without intermediate removal of imbibed bath, washing said layer with an inhibitor-dissolving aqueous alkaline solution until a positive color image has been developed therein.
 25. The process according to claim 24 wherein said inhibitor is sulfite.
 26. A color developer bath for photographic positive color development of silver halide photographic elements, said bath comprising, in aqueous solution of pH 8.5-14, A. at least 0.02 moles/liter of a photographic color developing agent capable of reacting with a photographic color coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 11.0 of from about -159 to about -305 millivolts; B. a black and white photographic developer including at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about -10 millivolts to about -187 millivolts; and C. a water-soluble, dye-formation inhibitor in a concentration of at least about 0.10 moles/liter which is capable of reacting with the oxidation product of said color developing agent to form a stable, soluble complex and which is present in sufficient quantity so that substantially all dye formation of a silver halide photographic element is restrained in said bath after exposure of said element to light, the mole ratio of inhibitor to color developer being at least about 0.97.
 27. A photographic color reversal development process which comprises A. treating a photographic element having a hydrophilic colloid silver halide layer bearing a latent image with an aqueous alkaline bath which includes at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation of reacting with a photographic color coupler to form a dye, black and white photographic developer including at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 of from about -10 millivolts to about -187 millivolts, and water-soluble dye-formation inhibitor in a concentration sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, and of at least about 0.10 moles/liter, the mole ratio of inhibitor to color developer being at least about 0.97, thereby to imbibe said silver halide layer with said bath and to develop solely a negative black and white silver image therein; B. thereafter fogging said silver halide layer so as to render said layer developable in non-imaged areas; and C. without intermediate removal of said imbibed bath, treating said layer to reduce the inhibiting effect of said dye formation inhibitor, thereby to cause development therein of a positive color image.
 28. A bath for photographic positive color development of silver halide photographic elements said bath comprising in aqueous solution at a pH of from 8.5-14; A. at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 11.0 of from about -159 to about -305 millivolts, B. at least one black-and-white developing agent having a polarographic half-wave potential at pH 10.0 of from about -10 millivolts to about -187 millivolts, and C. water-soluble, dye-formation inhibitor in a concentration which is sufficient so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97.
 29. The bath of claim 28 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid, 4-hydroxy-3-butanone and hydroquinone monocarboxylic acid hydrazides.
 30. A bath for photographic positive color development of silver halide photographic elements, said bath comprising in aqueous solution at a pH of from 8.5-14: A. at least 0.02 moles/liter of photographic color developing agent capable, upon oxidation thereof, of reacting with a photographic coupler to form a dye, said color developing agent having a polarographic half-wave potential at pH 11.0 of from about -159 to about -305 millivolts, B. at least one black and white developing agent having a polarographic half-wave potential at pH 10.0 greater than that of phenidone to -10 millivolts, and C. water-soluble, dye-formation inhibitor in a sufficient concentration so that substantially all dye formation of a silver halide photographic element is restrained in said bath after said element has been exposed to light, the mole ratio of inhibitor to color developer being at least about 0.97.
 31. The photographic developer bath of claim 30 in which dye formation inhibitor is present in a concentration of at least about 0.10 moles/liter.
 32. The bath of claim 30 wherein the dye formation inhibitor is selected from the group consisting of sulfite, ascorbic acid, citrazinic acid 4-hydroxy-3-butanone, and monocarboxylic acid hydrazides. 